1. Field of the Invention
This invention relates to a fuel-air mixture supply system whereby fuel in the fuel-air mixture produced in the carburetor is well vaporized and also the mixture is evenly distributed to the respective cylinders of the engine.
2. Description of the Prior Art
Generally, the fuel-air mixture produced in an internal combustion engine is supplied to the respective cylinders in the engine body through an intake manifold. It is, however, often experienced that fuel in the mixture would adhere to the riser of the intake manifold to hinder uniform supply of the mixture to the respective cylinders. Attempts have therefore been made to modify the internal configuration of the intake manifold or to heat the mixture to expedite vaporization of fuel. Nevertheless, these attempts were not sufficient to realize satisfactorily uniform feed of the mixture to the respective cylinders. Therefore, there still remained the problem that the engine performance is lowered when a lean mixture is supplied to the respective cylinders through the intake manifold, while harmful substances such as carbon monoxide (CO) and hydrocarbons (HC) in the engine exhaust gas are increased when a rich mixture is supplied to the intake manifold.